Development of a Lipoprotein Analyzer system is proposed for rapid analysis of and characterization of the HDL, LDL, and VLDL profiles of human blood plasma. Preliminary results using a prototype system demonstrated the potential of the proposed system: the HDL, and VLDL fractions were clearly separated, plasma samples were analyzed without sample pre- treatment, and differences in lipoprotein profiles were noted for different patients.Analyses times were between 20 minutes and 1 hour. Determination of accurate particle size of the lipoprotein complexes also demonstrated the unique capabilities of this system. The separation strategy of the proposed Lipoprotein Analyzer is based on Flow field- flow fractionation, (Flow FFF) an elution based technique. This methodology is capable of high resolution measurements and is bio- compatible for analysis of biological macromolecules ranging from proteins up to chromosomes and cells. Thus this instrumentation is potentially a powerful and effective tool for rapid and direct measurement of the entire subfraction set of the lipoprotein profile. The applicants propose to further study, optimize, and develop Flow FFF so as to ultimately generate a rugged, routine technique. They expect this development will provide a more expedient and less expensive method for lipoprotein characterization than currently available.